Impairment of red blood cell deformability by tumor growth.

Red blood cell deformability is a major determinant of capillary blood flow. In mice with L1210 leukemia and with Lewis lung carcinoma, red blood cell deformability was significantly decreased during tumor growth. In mice with L1210 leukemia, deformability was significantly decreased by day 5 after transplantation and progressively decreased through day 9. Terminally, red blood cell deformability returned to normal or above normal values. In mice with Lewis lung carcinoma, significant decreases in deformability were noted 21--28 days after transplantation and persisted throughout the remainder of the tumor course. Impaired capillary blood flow, secondary to abnormal red blood cell deformability, is therefore associated with advanced cancer.